Methods and Equipment

For our photogrammetric projects, we use only high quality system cameras with APS-C and  full-frame sensors. In this way, we can guarantee the production of quality photos for precise surveying even in poor light conditions.

After a number of sobering experiences with mass-market products, we decided to contract Soleon to produce aircraft customised to our exact needs and standards. On top of their very client-oriented business practices, they even went so far as to pre-design each object in 3D, with the help of FEM programmes, in addition to using the best materials on the market.

Survey Coanda Mk.AD

In early 2018 we decided to consolidate our fleet with uniform batteries, remote controls, flight controls and flight planning software. April 2018 brought the delivery of Survey Coanda Mk.AD by Soleon and it will be the successor to Surveying Robot Mk.AD for future photogrammetric projects.

Surveying Robot Mk.AD

The workhorse of our vehicle pool since 2015, the Surveying Robot Mk.AD is a hexacopter which can be adapted as required for working in mountains. Since its arrival, it has put in 126 flight hours carrying out commercial missions. 

Equipped with a biaxial gimbal, it can safely transport one of our Sony system cameras, complete with high quality Zeiss lenses, up to some 3,000m into the air.

Since early 2018, it has become our backup rig, ready for action should the Survey Coanda Mk.AD be under maintenance or, due to time constraints, should a second copter be required.

UAV planner 3D

The problem with photogrammetric flights is that it is relatively easy to plan such a mission in 2D: the overlap in the X and Y directions are at hand and the altitude remains constant. On flat land, this represents a simple exercise in geometry.

However the Earth is unfortunately not always as flat as the plains of Northern Germany. For precisely this reason, we have developed a tool with which you can also create plans for flights over hilly and mountainous areas.

Our goal was to keep the distance to the photographed object constant, regardless of whether the incline is 0° or 90°. Only in this way can we be sure that the overlapping and geometric resolution remain constant during the whole flight.

3D ImageVector UAV & EMLID Reach RS

Since mid-2017, our Surveying Robot Mk.AD has been equipped with a PPK-GNSS system so that it can collect photogrammetric data in impassable or dangerous areas without any significant loss of precision. This produces a handy side effect for more “standard” projects: the number of waypoints can be reduced without sacrificing accuracy.

In tandem with “3D ImageVector UAV” on the copter, a base station (“EMLID Reach RS”) is set up to simultaneously display the copter’s GNSS data. Through the underlying refinement provided by this arrangement, an ten-fold increase of accuracy in positioning of the exposures becomes attainable.

Helicopters

When legal or time constraints prevent the use of drones, we can also use a helicopter to gather the necessary images for photogrammetric processing. From the well-secured open cabin door, the project area will be photographed as per the appropriate overlapping. The exposures are then logged by “Image Vector” (made by REDcatch) to facilitate later processing.

A disadvantage of using a helicopter is the relatively imprecise flightplan, as even an adept pilot finds it nigh on impossible to maintain a steadily consistent distance to the ground. As such, a helicopter flight can often produce a very unhomogenized level of ground sampling distance.